This was a cute, quirky, fun read. As far as genres go, it's steampunk-romance-mystery with some supernatural elements (vampires, werewolves, and ghosts). The protangonist, Miss Alexia Tarabotti, is an on-the-shelf Victorian spinster, whose family considers her prospects hopeless because she is strong-willed, not conventionally pretty, and half-Italian (the horror!). She also happens to be preternatural - having the rare ability to counteract others' supernatural qualities due to being born without a soul.
The plot is good and quick paced, and Carriger has obviously done her research in creating a vivid Victorian world. The writing style is reminiscent of a period piece and the fantasy elements are sprinkled in to good effect without being overbearing. I must admit I'm really not a romance fan so I found certain scenes pretty cheesy, but that speaks purely to my genre preferences.
Overall, I definitely enjoyed this first installment in the Parasol Protectorate series, and I'll be sure to pick up the other books when I need a break from more serious literature.